[env-trinity] Trinity Flow Update

[Andrew_Hamilton at fws.gov]

With flows at 2,000 cfs, it would be worthwhile for anyone interested in
seeing how the river is supposed to work to go take a look.  This would be
a close to ideal mid-March to mid-May managed flow for the Trinity, working
with about half the natural average flow, around 650,000 acre-feet, which
would leave enough for a short gravel-stirring flow in May.

What 2,000 to 3,000 cfs does, if sustained, is maximize chinook rearing
habitat.  For what it's worth, it also makes about half the river down to
the North Fork look like ideal Trinity River steelhead spawning habitat--
if you judge that by the appearance at lower flows of the short reach from
about a hundred feet above Bucktail Bridge upstream to the riffle, which is
the river's primo steelhead spawning reach at the 300 cfs discharge.

Although the second week of March is a little early, if there has been
adequate seeding this year you can see the Trinity operating as a fish
factory along the edges from Lewiston down to Oregon Gulch and conceivably
to the North Fork.  There are several places that stand out:  the best
place to look on foot is the side-channel complex between Peterson Hole at
about the trailer park just below the Old Bridge in Lewiston, down to about
the old temporary rearing ponds at the sawmill.  At 2,000 cfs the river,
which usually breaks right and left over a low island, flows over the
island in a number of places, increasing Chinook rearing habitat a huge
amount.  If you slosh around in the tangle, you should be able to see
thousands of young-of-year chinook that wouldn't otherwise have survived.
It's a little rough in there at 2,000 cfs but the habitat gains are
impressive down into the 800 cfs range, so it would be worth a visit as the
flow comes down.  Other fairly accesible areas are the right bank just
above the Salt Flat bridge, at Steelbridge below the campground, and
side-channels or overflow in the Indian Creek area on the left bank above
the upstream houses.  There are also impressive accessible increases in
habitat on the right at Oregon Gulch where the river levels out, and below
Junction City on the right opposite J&M tackle if you can get in there, but
mid-March is usually too early to see a lot of juveniles that far
down-river.

By my observation and measurement, there is nothing particularly wrong with
the morphology of the river that 2,000 to 3,000 cfs doesn't correct just by
being there.  Anyone who is interested could take this opportunity and take
a few hours to to see  what water will do in the existing channel during
the early rearing season. Even if the river is murky, you can probably see
fish in the shallows, which is where a lot of them will be.

Regarding complaints about the murk, it isn't sand, and I doubt that it
hurts the fish.  It's probably Red Alps fines from mass wasting or sheet
erosion off logging sites above Trinity Lake, although I haven't looked to
see if the lake is murky.  This happened in 1986, when the river below
Lewiston was cloudy from February into early summer as a result of erosion
from logging on the Papoose arm.  As far as sand as high up as the Lewiston
area, some  comes out of Deadwood Creek, but most of it is apparently from
Hoadley Gulch, which is usually just a trickle. Back around 1990, the river
from the Old Lewiston Bridge down to the old gabion was back-hoed out to a
depth of about 16 feet, with the idea of providing holding habitat, and you
can see what Hoadley Gulch did to the hole when it rained hard.

Andrew Hamilton
US Fish and Wildlife Service
(916) 414-6540



                                                                                                                              
                      "Andreas Krause"                                                                                        
                      <AKRAUSE at mp.usbr.gov>                       To:      <env-trinity at velocipede.dcn.davis.ca.us>, "Andreas 
                      Sent by:                                    Krause" <AKRAUSE at mp.usbr.gov>                               
                      env-trinity-bounces at velocipede.dcn.         cc:                                                         
                      davis.ca.us                                 Subject: [env-trinity] Trinity Flow Update                  
                                                                                                                              
                                                                                                                              
                      05-03-2004 04:24 PM                                                                                     
                                                                                                                              
                                                                                                                              




The current Safety of Dams release of 2,000 cfs from Lewiston Dam to the
Trinity River is expected to continue at least until March 7 and
possibly extend through March 15, pending weather conditions.

__________________________________
Andreas Krause, P.E.
Physical Scientist
Trinity River Restoration Program
P.O. Box 1300 (mailing address)
1313 South Main St. (physical address)
Weaverville, CA 96093
Phone:530-623-1807; Fax 530-623-5944
__________________________________
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